splat 命令

Splat 将通过 AIX 跟踪命令收集的 AIX 跟踪文件作为主输入。 用 splat 分析跟踪前，您需要确保跟踪是用一组适当的 hook 来收集的， 包括以下内容：

106 DISPATCH
10C DISPATCH IDLE PROCESS
10E RELOCK
112 LOCK
113 UNLOCK
134 HKWD_SYSC_EXECVE
139 HKWD_SYSC_FORK
419 CPU PREEMPT
465 HKWD_SYSC_CRTHREAD
46D WAIT LOCK
46E WAKEUP LOCK
606 HKWD_PTHREAD_COND
607 HKWD_PTHREAD_MUTEX
608 HKWD_PTHREAD_RWLOCK
609 HKWD_PTHREAD_GENERAL

由于在多处理器环境中使用锁的频率，捕获这些锁和解锁跟踪事件可能导致严重的性能下降。 因此，通常禁用锁跟踪事件报告。 为了启用锁跟踪事件报告，在收集包含 splat 需要的（KornShell 语法）锁跟踪事件的跟踪前，必须采用以下步骤：

  1. bosboot -ad /dev/hdisk0 -L

  2. shutdown -Fr

  3. (reboot the machine)

  4. locktrace -S

  5. mkdir temp.lib; cd temp.lib

  6. ln -s /usr/ccs/lib/perf/libpthreads.a

  7. export LIBPATH=$PWD:$LIBPATH

步骤 1 至 3 是可选的。 它们启用显示内核锁类名而非地址。 请参阅 bosboot(1) 以获取有关 bosboot 及其标志的更多信息。 步骤 5 至 7 对于激活用户 pthread 锁检测是必要的；temp.lib 子目录可以放置在任何位置。 为了完成报告，步骤 1 到步骤 7 是必需的。

由 splat 生成的报告包含报告摘要、锁摘要报告部分和锁详细信息报告的列表，每个报告都可能有相关的函数详细信息报告和/或线程详细信息报告。

Report Summary
^^^^^^^^^^^^^^
 The report summary consists of the following elements:

 - The trace command used to collect the trace.
 - The host that the trace was taken on.
 - The date that the trace was taken on.
 - The duration of the trace in seconds.
 - The estimated number of CPUs
 - The combined elapsed duration of the trace in seconds;
   ( the duration of the trace multiplied by the number of
     CPUs identified during the trace ).
 - Start time, which is the offset in seconds from the beginning of the
   trace that trace statistics begin to be gathered.
 - Stop time, which is the offset in seconds from the beginning of the
   trace that trace statistics stop being gathered.
 - Total number of acquisitions during the trace.
 - Acquisitions per second, which is computed by dividing
   the total number of lock acquisitions by the real-time
   duration of the trace.
 - % of Total Spin Time, this is the summation of all lock spin hold
   times, divided by the combined trace duration in seconds, divided by 100.
   The current goal is to have this value be less than 10% of the total
   trace duration.


 Lock Summary
 ^^^^^^^^^^^^

 The lock summary report has the following fields:

Lock		         The name, lockclass or address of the lock.


Type              The type of the lock, identified by one of the following letters: 
                      Q    A RunQ lock 
                      S    A simple kernel lock 
                      D    A disabled simple kernel lock
                      C    A complex kernel lock 
                      M    A PThread mutex 
                      V    A PThread condition-variable 
                      L    A PThread read/write lock
Acquisitions     The number of successful lock attempts for this lock, minus
                  the number of times a thread was preempted while holding
                  this lock.

Spins            The number of unsuccessful lock attempts for this lock,
                  minus the number of times a thread was undispatched while
                  spinning.

Wait             The number of unsuccessful lock attempts that
 or               resulted in the attempting thread going to
Transform         sleep to wait for the lock to become available,
                  or allocating a krlock.

%Miss            Spins divided by Acquisitions plus Spins, multiplied by 100.

%Total           Acquisitions divided by the total number of all
                  lock acquisitions, multiplied by 100.

Locks/CSec       Acquisitions divided by the combined elapsed
 	               duration in seconds.

Percent HoldTime 
Real CPU          The percent of combined elapsed trace time that
                  threads held the lock in question while dispatched.
                  DISPATCHED_HOLDTIME_IN_SECONDS divided by combined
                  trace duration, multiplied by 100.

Real Elaps(ed)    The percent of combined elapsed trace time that
                  threads held the lock while dispatched or sleeping.
                  UNDISPATCHED_AND_DISPATCHED_HOLDTIME_IN_SECONDS divided
                  by combined trace duration, multiplied by 100.

Comb Spin         The percent of combined elapsed trace time that
                  threads spun while waiting to acquire this lock.
                  SPIN_HOLDTIME_IN_SECONDS divided by combined trace
                  duration, multiplied by 100.

锁摘要报告缺省为十个锁的列表，按轮转占用时间百分比（第十个字段）的降序排序。 摘要报告的长度可用 -S 开关调整。 摘要报告（和所有其他报告）的排序顺序可用 -s 开关设置，其选项在 SORTING 帮助部分（splat -h 排序）中描述。

Lock Detail
^^^^^^^^^^^

 The lock detail report consists of the following fields:

 LOCK             The address (in hexadecimal) of the lock.

 NAME             The symbol mapping for that address (if available)

 CLASS            The lockclass name (if available) and hexadecimal offset,
                  used to allocate this lock ( lock_alloc() kernel service ).

Parent Thread    Thread id of the parent thread. This field only exists for Mutex, 
                  Read/Write lock and Conditional Variable report. 

 creation time    Elapsed time in seconds after the first event recorded in trace, 
                  if available. This field only exists for Mutex, Read/Write lock
                  and Conditional Variable report.
 deletion time    Elapsed time in seconds after the first event recorded in trace, 
                  if available. Tthis field only exists for Mutex, Read/Write lock
                  and Conditional Variable report. 

 Pid              Pid number associated to the lock (this field only exists for Mutex, 
                  Read/Write lock and Conditional Variable report). 

 Process Name    Process name associated to the lock (this field only exists for Mutex, 
                 Read/Write lock and Conditional Variable report). 

 Call-Chain      Stack of called methods (if possible to have them, this field only 
                 exists for Mutex, Read/Write lock and Conditional Variable report). 


 Acquisitions     The number of successful lock attempts for this lock.
                  This field is named Passes for the conditional variable lock report.

 Miss Rate        The number of unsuccessful lock attempts divided by
                  Acquisitions plus unsuccessful lock attempts, multiplied
                  by 100.

 Spin Count       The number of unsuccessful lock attempts.

 Wait Count       The number of unsuccessful lock attempts that resulted in
                  the attempting thread going to sleep to wait for the lock
                  to become available.

 Transform Count  The number of krlock allocated and deallocated by the simple lock. 

 Busy Count	      The number of simple_lock_try() calls that returned busy.

 Seconds Held
 CPU              The total time in seconds that this lock was held by
                  dispatched threads.

 Elapsed	         The total time in seconds that this lock was held by
                  both dispatched and undispatched threads.

NOTE: neither of these two values should exceed the
      total real elapsed duration of the trace.

 Percent Held
 Real CPU         The percent of combined elapsed trace time that
                  threads held the lock in question while dispatched.
                  DISPATCHED_HOLDTIME_IN_SECONDS divided by trace
                  duration, multiplied by 100.

 Real Elaps(ed)   The percent of combined elapsed trace time that
                  threads held the lock while dispatched or sleeping.
                  UNDISPATCHED_AND_DISPATCHED_HOLDTIME_IN_SECONDS divided
                  by trace duration, multiplied by 100.

 Comb Spin        The percent of combined elapsed trace time that
                  threads spun while waiting to acquire this lock.
                  SPIN_HOLDTIME_IN_SECONDS divided by trace duration,
                  multiplied by 100. 

 Wait             The percentage of combined elapsed trace time that 
                  threads unsuccessfully tried to acquire this lock.

 SpinQ            Splat keeps track of the minimum, maximum and average
                  depth of the spin queue (the threads spinning, waiting
                  for a lock to become available).

 WaitQ            As with the spin queue, splat also tracks the minimum,
                  maximum and average depth of the queue of threads waited
                  waiting for a lock to become available).

PROD              The associated krlocks prod calls count.

CONFER SELF       The confer to self calls count for the simple lock and the 
                  associated krlocks.

CONFER TARGET     The confer to target calls count for the simple lock and the 
                  associated krlocks. w/ preemption reports the successfull calls 
                  count, resulting in a preemption.

CONFER ALL        The confer to all calls count for the simple lock and the 
                  associated krlocks. w/ preemption reports the successfull calls 
                  count, resulting in a preemption.

HANDOFF           The associated krlocks handoff calls count.

Lock Activity w/Interrupts Enabled (mSecs)

锁详细报告的这部分是 splat 收集的每个锁的原始数据的转储，时间以毫秒表示。 五种状态：锁、轮转、等待、未分派（atched）和占先是 splat 的已启用的 simple_lock 有限状态机的五种基本状态。 每一种状态的计数是导致转换为该状态的线程的操作次数。 以毫秒为单位的持续时间显示锁请求在此状态耗费的最小时间、最大时间及时间的总量。

   LOCK:    this state represents a thread successfully acquiring a lock.

   SPIN:    this state represents a thread unsuccessfully trying to acquire
            a lock.

   WAIT:    this state represents a spinning thread (in SPIN) going to sleep
            (voluntarily) after exceeding the thread's spin threshold.

   UNDISP:  this state represents a spinning thread (in SPIN) becoming
            undispatched (involuntarily) before exceeding the thread's
            spin threshold.

   PREEMPT: this state represents when a thread holding a lock is
            undispatched.


Lock Activity w/Interrupts Disabled (mSecs)

锁详细报告的这部分是 splat 收集的每个锁的原始数据的转储，时间以毫秒表示。 六种状态：锁、轮转、带 KRLOCK 的锁、KRLOCK 锁、KRLOCK 轮转和转换是 splat 的已禁用的 simple_lock 有限状态机的六种基本状态。 每一种状态的计数是导致转换为该状态的线程的操作次数。 以毫秒为单位的持续时间显示锁请求在此状态耗费的最小时间、最大时间及时间的总量。

LOCK:        This state represents a thread successfully acquiring a lock.

SPIN:        This state represents a thread unsuccessfully trying to acquire
             a lock.

LOCK with    The thread has successfully acquired the lock, while holding 
 KRLOCK:     the associated krlock, and is currently executing.

KRLOCK LOCK: The thread has successfully acquired the associated krlock, 
             and is currently executing.

KRLOCK SPIN: The thread is executing and unsuccessfully attempting to acquire
             the associated krlock. 

TRANSFORM:   The thread has successfully allocated a krlock it associates to, 
             and is executing.


Function Detail
^^^^^^^^^^^^^^^

 The function detail report consists of the following fields:

 Function Name   The name or return address of the function which
                 used the lock.

 Acquisitions	   The number of successful lock attempts for this lock.
                 For complex lock and read/write lock there is a 
                 distinction between acquisition for writing 
                 (Acquisition Write) and for reading 
                 (Acquisition Read).


 Miss Rate      The number of unsuccessful lock attempts divided by
                Acquisitions, multiplied by 100.

 Spin Count     The number of unsuccessful lock attempts.
                For complex lock and read/write lock there is a 
                distinction between spin count for writing 
                (Spin Count Write) and for reading 
                (Spin Count Read).

 Wait Count     The number of unsuccessful lock attempts that resulted in
                the attempting thread going to sleep to wait for the lock
                to become available.
                For complex lock and read/write lock there is a 
                distinction between wait count for writing 
                (Wait Count Write) and for reading 
                (Wait Count Read).

Transform Count The number of times that a simple lock has allocated a krlock,
                while the thread was trying to acquire the simple lock.

 Busy Count	     The number of simple_lock_try() calls that returned busy.

 Percent Held of Total Time 
 CPU              The percent of combined elapsed trace time that
                  threads held the lock in question while dispatched.
                  DISPATCHED_HOLDTIME_IN_SECONDS divided by trace
                  duration, multiplied by 100.

 Elaps(ed)	      The percent of combined elapsed trace time that
                  threads held the lock while dispatched or sleeping.
                  UNDISPATCHED_AND_DISPATCHED_HOLDTIME_IN_SECONDS divided
                  by trace duration, multiplied by 100.

 Spin             The percent of combined elapsed trace time that
                  threads spun while waiting to acquire this lock.
                  SPIN_HOLDTIME_IN_SECONDS divided by combined trace
                  duration, multiplied by 100.

 Wait             The percentage of combined elapsed trace time that 
                  threads unsuccessfully tried to acquire this lock. 

 Return Address   The calling function's return address in hexadecimal.

 Start Address	   The start address of the calling function in hexadecimal.

 Offset           The offset from the function start address in hexadecimal.


Thread Detail
^^^^^^^^^^^^^

The thread detail report consists of the following fields:

 ThreadID        Thread identifier.

 Acquisitions    The number of successful lock attempts for this lock.

 Miss Rate       The number of unsuccessful lock attempts divided by
                 Acquisitions, multiplied by 100.

 Spin Count      The number of unsuccessful lock attempts.

 Wait Count      The number of unsuccessful lock attempts that resulted in
                 the attempting thread going to sleep to wait for the lock
                 to become available.

Transform Count The number of times that a simple lock has allocated a krlock,
                while the thread was trying to acquire the simple lock.

Busy Count      The number of simple_lock_try() calls that returned busy.

 Percent Held of Total Time 
 CPU              The percent of combined elapsed trace time that
                  threads held the lock in question while dispatched.
                  DISPATCHED_HOLDTIME_IN_SECONDS divided by trace
                  duration, multiplied by 100.

 Elaps(ed)        The percent of combined elapsed trace time that
                  threads held the lock while dispatched or sleeping.
                  UNDISPATCHED_AND_DISPATCHED_HOLDTIME_IN_SECONDS divided
                  by trace duration, multiplied by 100.

 Spin             The percent of combined elapsed trace time that
                  threads spun while waiting to acquire this lock.
                  SPIN_HOLDTIME_IN_SECONDS divided by combined trace
                  duration, multiplied by 100. 

 Wait             The percent of combined elapsed trace time that 
                  threads unsuccessfully tried to acquire this lock. 

 ProcessID        Process identifier (only for SIMPLE and COMPLEX Lock report). 

 Process Name     Name of the process (only for SIMPLE and COMPLEX Lock report).

splat 允许用户指定使用哪个条件、使用 -s 选项对摘要和锁详细信息报告排序。 缺省排序条件是按轮转占用时间百分比排序，这是线程用于锁轮转的时间与总的跟踪持续时间的比率。 使用 -s，排序条件可变为以下值：